right angle

American  

noun

right angles plural

1. the angle formed by two radii of a circle that are drawn to the extremities of an arc equal to one quarter of the circle; the angle formed by two perpendicular lines that intersect; an angle of 90°.

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right angle British  

noun

1. the angle between two radii of a circle that cut off on the circumference an arc equal in length to one quarter of the circumference; an angle of 90° or π/2 radians

2. perpendicular or perpendicularly

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right angle Scientific  

/ rīt /

1. An angle having a measure of 90°.

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right angle Cultural  

1. An angle measuring ninety degrees, formed by the intersection of two perpendicular lines. (Compare acute angle and obtuse angle.)

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Other Word Forms

Derived Forms

• right-angled
  adjective

Inflected Forms

Nouns

• right angles
  plural

Etymology

Origin of right angle

Middle English word dating back to 1350–1400

Example Sentences

With scarcely a right angle, and therefore no fixed point for my eyes to rest, the interior kept giving me differing impressions.

From The Wall Street Journal • Mar. 6, 2026

It occurs when an electric current flows through a material while a magnetic field is applied at a right angle.

From Science Daily • Mar. 1, 2026

Viewed at the right angle, the piece resembles a giant eye.

From Los Angeles Times • Feb. 2, 2026

But it also has an amazing property: If two lines on the Earth’s surface meet at a right angle in reality, they will still do so on the map.

From Slate • Jan. 21, 2026

It’s spray-painted in red on the blank expanse of wall above the staircase leading to the second story—that large X with each arm continued at a right angle.

From "Linked" by Gordon Korman